Synthesis of benzimidazoles containing pyrazole group and quantum chemistry calculation of their spectroscopic properties and electronic structure.

Five benzimidazole compounds containing pyrazole group were synthesized via one-step reaction of o-phenylenediamine and 1-arylpyrazole-4-carbaldehyde in ethanol under mild conditions. The composition and structure of resultant benzimidazole compounds were analyzed by means of elemental analysis, mass spectrometry, (1)H-nuclear magnetic resonance spectroscopy and X-ray single crystal diffraction. The ultraviolet-visible light spectra and fluorescent spectra of the products were measured. Their ground-state (S(0)) equilibrium geometries and vibrational frequencies were determined based on B3LYP method, and their first excited-state (S(1)) geometries were fully optimized based on 6-31G (d, p) basis set of TD-B3LYP method. Besides, the spectroscopic properties of the products were computed based on cc-pVTZ basis set of TD-B3LYP method and compared with corresponding experimental data. It has been found that benzimidazole compounds containing pyrazole group can be readily synthesized in a high yield via one-step reaction of o-phenylenediamine and 1-arylpyrazole-4-carbaldehyde in ethanol solvent. The fluorescence properties of the five synthesized compounds are closely related to their molecular structure; and their computed fluorescence spectra well correspond to their experimental values. Moreover, they have stable structure and strong fluorescence, showing potential application in time-resolved fluoroimmunoassay and DNA probe.

Syntheses and fluorescence properties of two novel lanthanide (III) perchlorate complexes with bis(benzylsulfinyl)methane.

A novel ligand with double sulfinyl groups, bis(benzylsulfinyl)methane, was synthesized by a new method and its two lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, (1)HNMR and UV spectra. The results indicated that the composition of these complexes was REL(2.5)(ClO(4))(3)·3H(2)O (RE = Tb (III), Dy (III), L = C(6)H(5)CH(2)SOCH(2)SOCH(2)C(6)H(5)). The FT-IR results revealed that the perchlorate group was bonded with the lanthanide ion by the oxygen atoms, and the coordination was bidentate. The fluorescent spectra illustrated that both the Tb (III) and Dy (III) complexes displayed characteristic fluorescence in solid state, especially for the Tb (III) complex, the peak of (5)D(4) → (7)F(5) of the Tb (III) ion in 544 nm was stronger than that of others. It indicated that the Tb (III) complex could emit purer green fluorescence. By analysis fluorescence and phosphorescence spectra, it was found that the ligand had the advantage to absorb energy and transfer it to the Tb (III) and Dy (III) ions. The phosphorescence spectra and fluorescence lifetimes of the complexes were also measured.

Fluorescence enhancement of rare earth Tb(III) by Tm(III) in benzyl benzoylmethyl sulphoxide complexes.

A series of rare earth complexes [(Tb(x) Tm(y))L5 (ClO4)2](ClO4)·3H(2) O (x:y = 1.000:0.000, 0.999:0.001, 0.995:0.005, 0.990:0.010, 0.950:0.050, 0.900:0.100, 0.800:0.200, 0.700:0.300; L = C(6) H5 CH2 SOCH2 COC6 H5) (Tb(III) luminescence ion; Tm(III) doped inert ion) were synthesized and characterized by elemental analysis, infrared spectra (IR) and (1) H-NMR. The photophysical properties of these complexes were studied in detail using ultraviolet absorption spectra, fluorescent spectra and lifetimes. The fluorescence spectra of complexes indicated that the fluorescence emission intensity was significantly enhanced by Tm(III). The complexes showed the best luminescence properties when the mole ratio Tb(III):Tm(III) was 0.990:0.010. The fluorescence intensity could be increased to 390%. Additionally, phosphorescence spectra and the luminescence mechanisms are discussed.

Fluorescence emission mechanism and fluorescence properties of ternary Tb(III) complex with diphenyl sulphoxide and bipyridine.

A novel ternary complex, TbL(5) L'(ClO(4))(3) · 3H(2)O, two binary complexes, TbL(7) (ClO(4))(3) · 3H(2)O and TbL'(3.5) (ClO(4))(3) · 4H(2)O has been synthesized (using diphenyl sulphoxide as the first ligand L, bipyridine as the second ligand L'). Their composition was analysed by element analysis, coordination titration, IR spectra and (1) H-NMR, and the fluorescence emission mechanism, fluorescence intensities and phosphorescence spectra were also investigated by comparison. It was shown that the ternary rare-earth complex showed stronger fluorescence intensities than the binary rare-earth complexes in such material. The strongest characteristic fluorescence emission intensity of the ternary system was 8.23 times, 3.58 times as strong as that of the binary systems TbL(7) (ClO(4))(3) · 3H(2)O and TbL'(3.5) (ClO(4))(3) · 4H(2)O, respectively. By fluorescence analysis it was found that both diphenyl sulphoxide and bipyridine could sensitize the fluorescence intensities of rare-earth ions. In particular, in the ternary rare-earth complex, introduction of bipyridine was of benefit to the fluorescence properties of Tb(III).

The studies of enhanced fluorescence in the two novel ternary rare-earth complex systems.

Two novel ternary rare-earth complexes SmL(5).L'.(ClO(4))(2).7H(2)O and EuL(5).L'.(ClO(4))(2).6H(2)O (the first ligand L = C(6)H(5)COCH(2)SOCH(2)COC(6)H(5), the second ligand L' = C(6)H(4)OHCOO(-)) were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DSC, (1)HNMR and UV spectra. The detailed luminescence studies on the rare-earth complexes showed that the ternary rare-earth complexes presented stronger fluorescence intensities, longer lifetimes, and higher fluorescence quantum efficiencies than the binary rare-earth materials. After the introduction of the second ligand salicylic acid group, the relative emission intensities and fluorescence lifetimes of the ternary complexes LnL(5).L'.(ClO(4))(2).nH(2)O (Ln = Sm, Eu; n=7, 6) enhanced more obviously than the binary complexes LnL(5).(ClO(4))(3).2H(2)O. This indicated that the presence of both organic ligand bis(benzoylmethyl) sulfoxide and the second ligand salicylic acid could sensitize fluorescence intensities of rare-earth ions, and the introduction of salicylic acid group was a benefit for the fluorescence properties of the ternary rare-earth complexes. The fluorescence spectra, fluorescence lifetime and phosphorescence spectra were also discussed.

Synthesis and luminescence properties of two novel lanthanide (III) perchlorate complexes with bis(benzoylmethyl) sulfoxide and benzoic acid.

Two novel ternary rare earth complexes of Tb(III) and Dy(III) perchlorates with bis(benzoylmethyl) sulfoxide (L) and benzoic acid (L') had been synthesized and characterized by elemental analysis, coordination titration analysis, molar conductivity, IR, TG-DSC, (1)HNMR and UV spectra. The results indicated that the composition of these complexes was REL(5)L'(ClO(4))(2) x nH(2)O (RE = Tb(III), Dy(III); L = C(6)H(5)COCH(2)SOCH(2)COC(6)H(5), L' = C(6)H(5)COO; n = 6,8). The fluorescence spectra illustrated that the ternary rare earth complexes presented stronger fluorescence intensities, longer lifetimes and higher fluorescence quantum efficiencies than the binary rare earth complexes REL(5) x (ClO(4))(3) x 2 H(2)O. After the introduction of the second ligand benzoic acid group, the relative fluorescence emission intensities and fluorescence lifetimes of the ternary complexes REL(5)L'(ClO(4))(2) x nH(2)O (RE = Tb(III), Dy(III)) enhanced more obviously than the binary complexes. This indicated that the presence of both organic ligands bis(benzoylmethyl) sulfoxide and the second ligand benzoic acid could sensitize fluorescence intensities of rare earth ions, and the introduction of benzoic acid group was resulted in the enhancement of the fluorescence properties of the ternary rare earth complexes. The phosphorescence spectra were also discussed.

Synthesis and fluorescence properties of lanthanide (III) perchlorate complexes with naphthyl-naphthalinesulphonylpropyl sulfoxide.

A ligand with double sulfinyl groups, naphthyl-naphthalinesulphonylpropyl sulfoxide(dinaphthyl disulfoxide, L), was synthesized by a new method and its several lanthanide (III) complexes were synthesized and characterized by element analysis, molar conductivity, coordination titration analysis, IR, TG-DTA, (1)HNMR and UV spectra. The composition of these complexes, were RE(2)(ClO(4))(6).(L)(5).nH(2)O (RE = La, Nd, Eu, Tb, Yb, n = 2 approximately 6, L = C(10)H(7)SOC(3)H(6)SOC(10)H(7)). The fluorescent spectra illustrated that the Eu (III) complex had an excellent luminescence. It was supposed that the ligand was benefited for transferring the energy from ligand to the excitation state energy level ((5)D(0)) of Eu (III). The Tb (III) complex displayed weak luminescence, which attributed to low energy transferring efficiency between the average triplet state energy level of ligand and the excited state ((5)D(4)) of Tb (III). So the Eu (III) complex displayed a good antenna effect for luminescence. The phosphorescence spectra and the relationship between fluorescence lifetime and fluorescence intensity were also discussed.

The synthesis of nano-sized TS-1 zeolites under rotational crystallisation conditions can inhibit anatase formation.

Hydrothermal synthesis is a typical method for the preparation of TS-1. In the current study, agitation was introduced during the crystallisation stage, and nano-sized TS-1 with little anatase TiO2 was successfully synthesised in a short time (1-8 h). Furthermore, under rotational crystallisation conditions, a series of TS-1 samples was prepared with different crystallisation times, and the products obtained were investigated as catalysts for the oxidative desulfurisation of thiophene from a model fuel. All samples were characterised utilising X-ray diffraction (XRD), scanning electron microscopy (SEM), N2-adsorption, ultraviolet-visible (UV-Vis) spectroscopy and Fourier-transform infrared (FT-IR) spectroscopy techniques. It was found that under rotational crystallisation conditions, nano-sized TS-1 could be synthesised in a short time that had improved efficiency for the oxidative desulfurisation reaction of thiophene in comparison with TS-1 synthesised by static crystallisation for 24 h.

A facile hydrothermal method for preparation of fluorescent carbon dots on application of Fe3+ and fingerprint detection.

The carbon dots (CDs) was prepared by a facile hydrothermal treatment of citric acid and glycine at 180 °C. The CDs at around 3.2 nm was collected after filtration and dialysis. The sample displayed green fluorescence (G-CDs) with a quantum yield of 3.7% in high concentration and the strongest emission peak was at 545 nm under the excitation wavelength of 480 nm; the blue fluorescence CDs (B-CDs) with a quantum yield of 29.8% was obtained after diluted either in solution or in powder, the strongest emission peak was located at 475 nm under the excitation wavelength of 380 nm. The G-CDs possessed a high selectivity to Fe3+, which was in a linear range of 0-3.5 µM with the detection limit of 0.21 µM. The CDs powder with blue fluorescence at a relative low content was obtained and adaptable for the fingerprint detection on substrates of litmus paper, resin tabletop, glass, and orange plastic ruler.

Nitrogen-containing activated carbon of improved electrochemical performance derived from cotton stalks using indirect chemical activation.

Highly porous (specific surface area, SBET, 1400 m2/g) and rich in surface groups activated carbons (ACs) were obtained from cotton stalks using either a direct or indirect activation. They were characterized by adsorption of nitrogen, thermal analysis combined with mass spectrometry, potentiometric titration, and X-ray photoelectron spectroscopy (XPS). XPS analysis indicated that the indirect activation led to more nitrogen on the surface incorporated as pyridinic and graphitic/quaternary species. These species were beneficial for a carbon application as oxygen reduction reaction (ORR) electrocatalysts and supercapacitors. The carbons were catalytically active in ORR with a number of electron transfer from 2.15 to 3.40 and onset potential of 0.810 V vs. reference hydrogen electrode (RHE). Their capacitance was around 180 F g-1 at 1 A g-1 when measured in an alkaline medium. The dependence of the performance on the porosity and nitrogen content was found, indicating suitability of cotton stalks obtained using the indirect activation as precursors of carbons of promising electrochemically active features.

[Construction of thr461 --> Asn461 and Ile462 --> Val462 mutation vector of P4501A1 gene].

OBJECTIVE: To construct Thr461 --> Asn461 and Ile462 --> Val462 mutation vector of P4501A1 gene and to provide scientific base for deeply researching on the function of cytochrome 1A1 gene (CYP1A1) and the mechanism of carcinogenesis. METHODS: According to cDNA sequence of human CYP1A1 gene, universal primers (Pm3/Pm4) and mutant primers (Pt15/Pt16 and Pt17/Pt18) containing restriction enzyme site and mutation site were designed. The first set of primers involving Pm3/Pt16 and Pm3/Pt18 amplified a forward 1.5kb fragment from pGEM-T-CYP1A1 plasmid. The second set of primers involving Pt15/Pm4 and Pt17/Pm4 amplified a reverse 177-bp fragment from 10ng pGEM-T-CYP1A1 plasmid. The third set of primers involving Pm3/Pm4 amplified a 1.5kb fragment from the fomer PCR amplifications. The third PCR products were separated, purified and recovered from 1% agarose gel, then inserted into pMD-T vector. Subsequently the conjunct products were transformed into E. coil strain DH-5alpha., then the single clone was screened out and plasmids were extracted from such clone finally verified by restriction endonuclease analysis and sequencing. RESULTS: A 1.5kb fragment of tricycle PCR amplifications were digested by restriction endonucleases (BamHI and SailI) and sequenced bidirectionally by universal primers(T7p and SP6). The results verified that the cloned fragment including Asn461 and Val462 mutant site had 99.9% homology with the human cDNA of CYP1A1 gene in Genebank. CONCLUSION: The objective fragment containing Asn461 and Va462 mutant site with cDNA of the CYP1A1 gene has been successfully constructed in this experiment.

Mesoporous Phosphorus-Doped g-C3N4 Nanostructured Flowers with Superior Photocatalytic Hydrogen Evolution Performance.

Graphitic carbon nitride (g-C3N4) has been deemed a promising heterogeneous metal-free catalyst for a wide range of applications, such as solar energy utilization toward water splitting, and its photocatalytic performance is reasonably adjustable through tailoring its texture and its electronic and optical properties. Here phosphorus-doped graphitic carbon nitride nanostructured flowers of in-plane mesopores are synthesized by a co-condensation method in the absence of any templates. The interesting structures, together with the phosphorus doping, can promote light trapping, mass transfer, and charge separation, enabling it to perform as a more impressive catalyst than its pristine carbon nitride counterpart for catalytic hydrogen evolution under visible light irradiation. The catalyst has low cost, is environmentally friendly, and represents a potential candidate in photoelectrochemistry.

Aluminum-induced apoptosis in cultured cortical neurons and its effect on SAPK/JNK signal transduction pathway.

Aluminum exposure and apoptotic cell death has been implicated in several neurodegenerative diseases. The mechanisms by which aluminum interacts with the nervous system are only partly understood. In this study, we used cultured cortical neurons to investigate the ability of aluminum to induce the apoptosis of neurons and to explore the role of SAPK/JNK (stress-activated protein kinase or c-jun N-terminal kinase) signal transduction pathway on the apoptosis induced by aluminum. We found that aluminum-induced degeneration of cortical neurons involved the DNA fragmentation characteristic of apoptosis, and staining of aluminum-treated neurons with the DNA-binding fluorochrome Hoechst 33258 revealed the typical apoptotic condensation and fragmentation of chromatin. The rate of apoptosis increased significantly (from 4.9 to 13.1, 21.4, and 59.8%, P<0.01), which was measured by TdT-mediated dUTP nick end labeling. Western blot analysis showed that SAPK/JNK activities of cortical neurons varies when the exposure time of AlCl(3) were different. The phosphorylation levels were 4.2, 3.3, 1.9 and 1.1 times greater compared to control cultures for 6, 12, 24, and 48 h, respectively (P<0.01). Furthermore, a JNK pathway inhibitor, CEP-11004 (KT8138) inhibited the activation of SAPK/JNK to protect cortical neurons from apoptosis induced by aluminum chloride. Our study demonstrates that aluminum can induce the apoptosis of cortical neurons and SAPK/JNK signal transduction pathway may play an important role in the apoptosis.

Thermally stable macroporous zirconium phosphates with supermicroporous walls: a self-formation phenomenon of hierarchy.

A self-formation phenomenon leading to the hierarchically thermally stable macroporous zirconium phosphates with amorphous supermicroporous walls from the precursors of zirconium propoxide and orthophosphoric acid solution was observed.

[Impact of low-level lead exposure on neural cell adhesion molecule expression of primarily cultured hippocampal neurons].

OBJECTIVE: To study the impact of low-level lead exposure on neural cell adhesion molecule (NCAM) expression of primarily cultured hippocampal neurons. METHODS: Wistar rats gestated at 18th day were anaesthetized and paunched to get the pups, the hippocampi of the pups were separated and the hippocampal neurons were primarily cultured. After co-cultivated with different dosage of PbCl(2), the NCAM expression of the neurons were tested with Western blotting at different culture time. RESULTS: Normally, the expression of NCAM at the 1st culture day was very low and its integral obsorbency density was 14; the climax expression time of NCAM of the cultured hippocampal neurons was 3rd to 5th cultured day, and their integral obsorbency density were 2 542 to 2 580; henceforth, the NCAM expression declined. NCAM expression was inhibited significantly by lead during the 2nd to 4th cultured day, and dose-response relationship was observed. The inhibition of lead weakened along with the cultured time prolonged, at 5th cultured day, it disappeared, and the NCAM expression of 10(-2), 10(-3) and 10(-4) mmol/L groups even exceeded the control groups. After that, the expression of NCAM in all groups began to decline, and the dose-response relationship of lead to the NCAM expression was observed again. CONCLUSION: Low-level lead might significantly inhibit the NCAM expression of the primarily cultured Wistar rats' hippocampal neurons, and might delay the climax NCAM expression time.

Hollow cobalt phosphonate spherical hybrid as high-efficiency Fenton catalyst.

Organic-inorganic hybrid of cobalt phosphonate hollow nanostructured spheres were prepared in a water-ethanol system through a mild hydrothermal process in the absence of any templates using diethylenetriamine penta(methylene phosphonic acid) as bridging molecule. SEM, TEM and N2 sorption characterization confirmed a hollow spherical micromorphology with well-defined porosity. The structure and chemical states of the hybrid materials were investigated by FT-IR, XPS and thermogravimetric analysis, revealing the homogeneous integrity of inorganic and organic units inside the network. As a heterogeneous catalyst, hollow cobalt phosphonate material exhibited considerable catalytic oxidizing decomposition of methylene blue with sulfate radicals as compared to cobalt phosphonate nanoparticles synthesized in single water system, which could be attributed to enhanced mass transfer and high surface area for the hollow material. Some operational parameters, including pH and reaction temperature, were found to influence the oxidation process. The present results suggest that cobalt phosphonate material can perform as an efficient heterogeneous catalyst for the degradation of organic contaminants, providing insights into the rational design and development of alternative catalysts for wastewater treatment.

Zn/Mn-MOFs with `S-shaped' packing modes.

Two novel polymers exhibiting metal-organic frameworks (MOFs) have been synthesized by the combination of a metal ion with a benzene-1,3,5-tricarboxylate ligand (BTC) and 1,10-phenanthroline (phen) under hydrothermal conditions. The first compound, poly[[(µ4-benzene-1,3,5-tricarboxylato-κ(4)O:O':O'':O''')(µ-hydroxido-κ(2)O:O)bis(1,10-phenanthroline-κ(2)N,N')dizinc(II)] 0.32-hydrate], {[Zn2(C9H3O6)(OH)(C12H8N2)2]·0.32H2O}n, denoted Zn-MOF, forms a two-dimensional network in which a binuclear Zn2 cluster serves as a 3-connecting node; the BTC trianion also acts as a 3-connecting centre. The overall topology is that of a 6(3) net. The phen ligands serve as appendages to the network and interdigitate with phen ligands belonging to adjacent parallel sheets. The second compound, poly[[(µ6-benzene-1,3,5-tricarboxylato-κ(7)O(1),O(1'):O(1):O(3):O(3'):O(5):O(5'))(µ3-hydroxido-κ(2)O:O:O)(1,10-phenanthroline-κ(2)N,N')dimanganese(II)] 1.26-hydrate], {[Mn2(C9H3O6)(OH)(C12H8N2)]·1.26H2O}n, denoted Mn-MOF, exists as a three-dimensional network in which an Mn4 cluster serves as a 6-connecting unit, while the BTC trianion again plays the role of a 3-connecting centre. The overall topology is that of the rutile net. Phen ligands act as appendages to the network and form the `S-shaped' packing mode.

Hollow manganese phosphonate microspheres with hierarchical porosity for efficient adsorption and separation.

Hollow manganese phosphonate microspheres of an inorganic-organic hybrid with hierarchically porous shells were prepared through a template-free hydrothermal method using ethylene diamine tetra(methylene phosphonic acid) as the coupling molecule. The hollow structures with hierarchical porosity were confirmed by SEM, TEM and N2 sorption. FT-IR, XPS and TG-DSC measurements revealed that the organophosphonate linkers were homogeneously incorporated into the hybrid framework. The hierarchical manganese phosphonates could be used as efficient adsorbents for the removal of copper ions, showing fast binding kinetics due to the well-structured porosity. The adsorption process follows pseudo-second order reaction kinetics, as well as Langmuir isotherm, indicating that Cu(2+) was monolayer adsorbed on the hybrid by chemical complexation. Furthermore, the synthesized manganese phosphonates with peculiar porosity exhibited excellent size selectivity for protein adsorption in a complex solution, presenting the promising potential as candidates for biomaterials.

Mesoporous cerium phosphonate nanostructured hybrid spheres as label-free Hg²âº fluorescent probes.

Porous phosphonate-based organic-inorganic hybrid materials have been shown to have novel and amazing physicochemical properties due to the integration of superiorities from both inorganic components and organic moieties. Herein, mesoporous cerium phosphonate nanostructured hybrid spheres are prepared with the assistance of cationic surfactant cetyltrimethylammonium bromide while using ethylene diamine tetra(methylene phosphonic acid) as the coupling molecule. The resulting hybrid is constructed from the cerium phosphonate nanoparticles, accompanied by high specific surface area of 455 m(2) g(-1). The uniform incorporation of rare-earth element cerium and organophosphonic functionalities endows mesoporous cerium phosphonate with excellent fluorescence properties for the development of an optical sensor for selective Hg(2+) detection on the basis of the fluorescence-quenching mechanism. The signal response of mesoporous cerium phosphonate against the Hg(2+) concentration is linear over the range from 0.05 to 1.5 µmol L(-1), giving a limit of detection of 16 nmol L(-1) (at a signal-to-noise ratio of 3). Most of the common physiologically relevant cations and anions did not interfere with the detection of Hg(2+). This label-free system provides a promising platform for further use in bioimaging and biomedical fields.

Adsorption of Cu(2+) and methyl orange from aqueous solutions by activated carbons of corncob-derived char wastes.

Corncob-derived char wastes (CCW) obtained from biomass conversion to syngas production through corncob steam gasification, which were often discarded, were utilized for preparation of activated carbon by calcination, and KOH and HNO3 activation treatments, on the view of environment protection and waste recycling. Their adsorption performance in the removal of heavy metal ions and dye molecules from wastewater was evaluated by using Cu(2+) and methyl orange (MO) as the model pollutant. The surface and structure characteristics of the CCW-based activated carbons (CACs) were investigated by N2 adsorption, CO2 adsorption, FT-IR, and He-TPD. The adsorption capacity varied with the activation methods of CACs and different initial solution concentrations, indicating that the adsorption behavior was influenced by not only the surface area and porosity but also the oxygen functional groups on the surface of the CACs. The equilibrium adsorption data were analyzed with the Langmuir, Freundlich, and Temkin isotherm models, and the adsorption kinetics was evaluated by the pseudo-first-order and pseudo-second-order models.